This is really a magic trick, but it is the best one I have seen in years.

The magician puts a stack of real quarters on his felt table top (you get to
touch them). He hands you a shot glass to show it to is ungimmicked, and
then slowly places the shot glass over the stack of 4 coins and lifts the
shot glass--all very slowly--your observing face a foot or so away. there
are only 3 coins.

He repeats this slow covering and uncovering of the coins with the clear shot
glass, and each time there is one less coin, until there are none. Nothing is
done fast, the coins are real and so is the shot glass.